I almost think a few gold mines in general around India, with two in Golconda would do, but it's your call, so long as there's at least something to make up for it.
As for the muskets, giving them a unit using the Turkish musket while improving Indian gunners somewhat (Perhaps to 16 or 17 damage to show the great craftsmanship and increased amount of gunpowder being used) is acceptable.
Weapon upgrades is a great idea! I'm impressed at your like for constructive criticism.